sedimentary
Flint / Chert
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically dark gray, black, or brown with a waxy to vitreous luster, conchoidal fracture, and no cleavage.
Identified More sedimentary →
Explore Flint / Chert in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, typically dark gray, black, or brown with a waxy to vitreous luster, conchoidal fracture, and no cleavage.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich solutions in marine environments during the Cretaceous and other periods.
Uses & applications
Historically used for making stone tools, weapons, and fire-striking; currently used in abrasives and decorative gravel.
Geological facts
Flint is a variety of chert that occurs specifically in chalk or marly limestone. It produces sharp edges when fractured, making it ideal for ancient tools.
Field identification & locations
Easily identified by its conchoidal fracture and hardness that scratches glass; commonly found in gravel deposits, chalk cliffs, and riverbeds.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary